Key

In case of theft or damage, there should be a reasonably fast and efficient way to get a replacement.

Local phones also come with the right fonts/character set, dates, voltages, and plugs needed in-country

Availability of local servicing outlets in case of device damage and need for repair

If not sourcing locally:

Unlocked. Particularly if sourcing a phone from a high-income country, many phones get locked into particular network providers and

Correct frequency band for the country of deployment

Correct languages are available by default (i.e. phone purchased in US might need to support French language for West Africa)

Accessories (might include SD card, SIM cards (Note: verifying that the device can accept a SIM card is especially important when looking at Tablets. Many popular models come in both SIM and WiFi only varieties), solar chargers, extra batteries, extra chargers (if poor quality grid electricity), plug adapters (if sourced from somewhere with different plugs), locks or boxes to prevent theft (if phone is attached to a facility), engraver to label devices (to prevent theft)...

Battery life. This is particularly important if you're working in rural areas where access to power can be infrequent or expensive.

Longevity of the platform. Will the model you choose still be available in-country in 3 years, 5 years, 10 years?

Likelihood of theft. Is the phone similar to others in the region or will it stand out as obviously a higher-end phone?